NEW ULM — Jefferson Middle School was briefly under a lockdown Friday after a student found an empty shell casing behind a door on the school property.

The student who found the casing alerted a teacher who in turn alerted Jefferson’s administration. The schools at the main campus were put on lockdown for precaution as law enforcement and administration conducted interviews and searched areas.

Upon further interviews, and a search of personal items and lockers, only the shell casing was found. No firearms were found at the school.

Once the building was deemed safe, all lockdowns were lifted and school returned to regular session.

Supt. Jeff Bertrang said the incident was initially reported at 9:23 a.m. and the lockdown was lifted at 10:08 a.m. after less than an hour.

In a message to parents, Supt. Intendent Bertrang said:

“We take all reports seriously and encourage parents to have conversations with their students regarding guns, ammunition and anything that may resemble a weapon and how they are not to be taken to school. We appreciate that a student stepped forward with concerns and reported the concerns to a teacher and administration.”